The invention relates to a method and a device for contacting the winding wire of a coil to a connecting pin by an end section of the winding wire being wound around an end section of the connecting pin using a plurality of turns, the connecting pin then being brought into contact with a fluxless soft solder and the latter finally being fused at a soldering temperature under a protective gas by feeding heat in a contactless fashion.
In order to avoid the undesired fluxes and solder baths in the production of relay coils, EP-0 651 407-A1 proposes a connection by means of a soft solder which is fused in a fluxless fashion under a protective gas. A proposed, preferred method is an arc/inert-gas soldering, which is analogous to the already known WIG welding (tungsten/inert-gas welding), and in which the connecting pin itself is not being fused together with the winding wire as in the case of the welding method, but the arc is dimensioned such that only the soft solder is liquefied. In this way, the thermal loading is significantly reduced for the coil former and the winding wire.
In the case of the WIG soldering described there, the arc is struck between the connecting pin and a counter-electrode. However, in this process problems could arise whenever, for example in the case of coils for miniature relays, connecting pins are used whose thickness is much less than 1 mm, that is to say 0.2 to 0.4 mm, for example. Such connecting pins can be contacted only with difficulty because of the correspondingly small coil dimension and their own cross-section. Under some circumstances the pins are even no longer capable of conducting the minimum current of, for example, 1A which can be generated in the case of customary WIG current sources.